Kariva and Period

Dana
I have been getting my period for about a day or two and then 2 weeks later again for a day or two. This has been happening for about 3 months. Last time I got my period (July 14) it was heavier than usual and lasted longer than usual. I haven't had my period since. 
We use a condom during sex. Although once in a while when we fool around he will put it in for a couple seconds. 
I am not experiencing any symptoms of pregnancy. And there have been times where I would get my period once every couple of months. I don't know what to think.